Projects within this Program propose to study many known and/or putative proteins using immunoprecipitation, immunoblot, radioimmunoassay, immunohistochemistry or immunoneutralization techniques. These methods require high affinity, high titer antibodies of appropriate specificity. This core will provide polyclonal antisera produced in rabbits or guinea pigs needed by the Projects participating in this program. We will use synthetic peptides conjugated to large carder proteins or fusion proteins as immunogens to develop antibodies directed towards gene products predicted from the cDNA sequences or from amino acid sequencing of tryptic fragments of purified natural products. These antisera raised against synthetic peptides will be evaluated with regard to titer and affinity for the synthetic immunogen using solid phase enzyme-linked immunosorbent assays (ELISAs). Furthermore, Core Component C will assist the Projects to determine the ability of antisera to recognize native or expressed proteins and the application of each antiserum in immunoblot, immunoprecipitation, immunoneutralization and immunohistochemical techniques.